Comparison of ICT equipment air-intake temperatures between cold aisle containment and hot aisle containment in datacenters

The objective of this paper is to clarify the differences between cold aisle containment (CAC) and hot aisle containment (HAC) with regard to the air-intake temperature of the ICT equipment in the rack. Thus, we constructed a system in which these two capping methods could be compared under the same load and air-conditioned environment, and measured those thermal environments. When the ICT equipment is installed vertically in the middle of the rack, the air-intake temperature with CAC was lower than that with HAC. The average difference was 1°;C, and 3°;C on the upper intake side. We also adjusted the air-intake temperatures of the ICT equipment to the equivalent level under both types of aisle containment by controlling the air-conditioning supplied air volume. As a result, when each air-intake temperature was kept at the same level under capping methods in the test environment, the air-conditioning fan power consumption with HAC was twice that with CAC. This demonstrates that the CAC can save more energy consumed by air-conditioning systems as it easily retains the low temperature conditions.